As seen in FIG. 5 many manufacturers use a standard type cabinet which provides multiple numbers of recessed areas with trays which hold, for example, rack mountable cartridge tape units, and which can be placed into the recesses for positioning and support.
Generally, highly dense items such as rack mountable cartridge tape modules are supported by a tray unit such as tray 20 of FIGS. 1 and 2 which are located in the recessed areas 11 shown in FIG. 5.
FIG. 5 shows a typical cabinet unit 10 having slot or recessed areas 11 into which may be placed heavy duty electronic equipment such as a typical rack mountable cartridge tape module. Such a unit might, for example, be installed in the recessed area 16 of FIG. 5.
The problem arises in many cases where the tray, in its standard format, does not provide sufficient stiffness to support the weight and various configurations of the tape module which it was required to hold.
Typical bending distortion and deflection measurements performed on such a standard cabinet and tray units showed that the mounted cartridge tape module would deform the tray unit by an amount, for example, of 6/100 of an inch while the appearance requirements of the design would allow only a 1/100 of an inch deflection.
Increasing the thickness of the tray unit 20 would in some respect increase the stiffness of the support. However this would be costly and time consuming and would require special configurations for special types of electronic modules and rack mounted cartridge tape modules.
As seen in FIG. 5, with the installation of a electronic module 16, the standard cabinet 10 would distort at the areas 12 and 14 considerably more than would be permissible for appearance and safety purposes.
The normal design for the internal tray units of the cabinet 10 of FIG. 5 basically utilized a tray unit 20 having a flat base plate 26 (FIGS. 1 and 2) to carry the load of the installed modules. The weight and center of gravity of these modules would vary depending on the module configuration and thus the support tray unit 20 and its base plate 26 could be loaded at one time with a particular module and at other times with a variety of different types of modules in the recessed area slots 11 of FIG. 5. Thus various different weight forces would be applied to a tray unit which would require different thickness trays leading t problems of supplying different thickness tray units for various modules loaded onto the tray units.
Calculations done by load analysis of the cabinet tray's original design have indicated that the tray unit thickness would have to increase considerably to provide the required stiffness to handle a range of different module loads. However such an increase in the tray thickness would not only be costly but involve considerable redesign from the standard trays which were being used. Further, developing a tray of varying thickness would involve unwanted time and expense, and potentially, a specially designed tray unit might be required for each combination of modules in the cabinet 10.
In order to take care of the problem where unsatisfactory distortions would occur at the areas 12 and 14 of FIG. 5, and other similar support areas in the cabinet 10, it was discovered that the idea of an adjustable deflection spring plate could be developed to engage the weight of the installed module on the tray unit. A concept of this spring plate was conceived as being fashioned by means of cutting it out of the tray unit and bending the finger plate at a specified angle .PHI. and/or alternatively developing a spring plate which could be applied with screws to the side walls 22, 24 of the tray unit 20.
By manipulating the geometry of the situation, selecting the material and the initial deflection of the spring plate, the weight of the inserted module would be supported by the spring plate 23, 25 into a coplanar condition with the base plane 26. As a result, the distortion appearance and deflection gaps could be controlled for various weights and centers of gravity of modules.
Thus the deflected spring plate and its variations was developed to provide an adjustable support that would control tray distortions for modules of any weight which were mounted on suspended flat plates while at the same time minimizing the final cabinet space requirements and the cabinet mass requirements with a supporting structure.